Hi,
The answer is c. The sample is biased.
This is because the sample is taken on a single state, an Rebecca reports a statistic about the nation. Her data contains information only of her state. If she lives in a very cold state, there is probably more homeowners using electric heat than in a hot state.
Answer: OPTION D.
Step-by-step explanation:
For this exercise it is important to remember the following Trigonometric Functions:

Knowing this, we can identify that:

Therefore, the ratio
is equivalent to this Trignometric function:

-2x+10=-5x-2
-2x+5x=-2-10
3x=-12
x=-12/3
x=-4
From the given situation above, here is the solution:
Friend A. 13 hours x $ 6.95 = $90.35 x 8 weeks = $722.80
Friend B. 15 hours x $ 5.85 = $87.75 x 8 weeks = $702
Friend C. 18 hours x $ 5.25 = $94.5 x 8 weeks = $756
Friend D. 11 hours x $ 7.80 = $85.8 x 8 weeks = $686.40
Therefore, the individuals who reached their goal of saving $720 for a vacation are friend A and friend C. The correct answer is option A. A and C.
What do you need to know for what?